Studies on electroless nickel–PTFE composite coatings

Abstract

Electroless deposition of nickel based composites produces outstanding tribiological behaviour. These composite coatings are formed by addition to the electroless nickel solution of the material to be codeposited, in powder form, and by maintaining it in suspension during the deposition process so that it is incorporated into the deposit. The most commonly used hard dispersed compounds are SiC, diamond powder, alumina, TiC, BN, chromium carbide or WC. Recently, electroless nickel containing PTFE as a composite material has been used because it is uniform, highly adherent, hard wearing, dry lubricating, non-galling, has a lower coefficient of friction and good corrosion resistance properties. The present paper studies the effect of PTFE in an electroless Ni–acid bath on the rate of deposition, incorporation of PTFE and phosphorous content in the deposit, wear and corrosion resistance.